A process of manufacturing acrylonitrile or methacrylonitrile by the catalytic reaction in the vapor phase of a paraffin selected from propane and isobutane with molecular oxygen and ammonia by catalytic contact of the reactants in a reaction zone with a catalyst, the feed composition having a mole ratio of the paraffin to ammonia in the range of from about 2.5 to 16 and a mole ratio of paraffin to oxygen in the range of from about 1.0 to 10, wherein said catalyst has the elements in the proportions indicated by the empirical formula:VSb.sub.m A.sub.a D.sub.b Q.sub.q R.sub.r O.sub.xwhereA is one or more of Ti, Sn, Fe, Cr and Ga;D is one or more of Li, Mg, Ca, Sr, Ba, Co, Ni, Zn, Ge, Zr, Cu, Ta, Bi, Ce, In, B and Mn;Q is one or more of Mo, W, and Nb;R is one or more of As, Te, and Se;m equals 0.8 to 4;a equals 0.01 to 2;d is 0 to 2;0.ltoreq.q